Apparatus and method for removing carrier film from a singulated die

ABSTRACT

An apparatus which reduces the surface area with which a carrier film adheres to a die, including a plate member including laterally spaced supports. Preferably, the apparatus also includes a vacuum source operatively connected to the plate member. Upon placement of a carrier film having an array of semiconductor dice adhered thereto onto the plate member, the dice are proximate the supports. The vacuum pulls air from the spaces between the supports, which partially releases the carrier film from the bottom surface of at least some of the dice. The apparatus may also include a die removal mechanism such as a vacuum collet type die pick-up mechanism, an extendable member die plunge-up mechanism, or a combination thereof. The present invention also includes a method for reducing the surface area with which a carrier film adheres to a die to facilitate removal thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of application Ser. No.09/304,566, filed May 4, 1999, pending, which is a divisional ofapplication Ser. No. 09/140,920, filed Aug. 26, 1998, now U.S. Pat. No.6,202,292 B1, issued Mar. 20, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to apparatus for removal of acarrier film from the bottom surface of semiconductor dice and otherelectronic devices. Particularly, the apparatus of the present inventionreduces the surface area of the adhesive film which remains in contactwith a die during removal. The present invention also relates to amethod for removing semiconductor dice and other electronic devices fromcarrier film.

[0004] 2. Background of Related Art

[0005] Several apparatus and methods are known for removingsemiconductors and other electronic devices from adhesive carriers suchas film. Some such methods involve degrading the adhesive properties ofthe carrier. Some devices employ needles, pistons, or other mechanismswhich apply an upward force to push the die off of the carrier. Otherdevices utilize a vacuum to pull a die from a carrier. Many knownapparatus and methods for removing a die from a carrier cause damage toa significant quantity of dice.

[0006] U.S. Pat. No. 4,778,326, issued in the names of Althouse et al.,discloses a method and apparatus for transporting semiconductor dicewhich is commonly referred to as a “gel pack” or “die-pac.” Thesemiconductor dice are loaded onto and adhere to a flat, thin, flexiblesilicone film, which is attached to a carrier base. The carrier base hasrecesses formed therein, into which the silicone film may be pulled as avacuum is applied beneath the film. As the film is pulled into therecesses, the area of the silicone film which contacts the dice isreduced, thereby reducing the magnitude of the adherence by which thedice are attached to the film. The dice may then be easily removed witha vacuum tip.

[0007] As mentioned above, the predominant use of gel packs is totransport dice. No semiconductor fabrication processes are performedwhile dice are on a gel pack. Use of gel packs is somewhat undesirablebecause the silicone of the films tends to contaminate dice by leaving asilicone residue thereon.

[0008] U.S. Pat. No. 5,590,787, issued in the name of Hodges, disclosesanother diepac device for transporting semiconductor dice. The device ofthe '787 patent includes a UV sensitive adhesive and permits thepenetration of electromagnetic radiation, such as ultraviolet light,therethrough.

[0009] Techniques which utilize carrier films having ultraviolet light(UV) degradable adhesives thereon or other degradable adhesives are alsowell known in the art. The area of film attached to a die which has beenselected for further manufacture is irradiated with the appropriatedegradative source to remove the die from the film. Although the use ofUV radiation and similar methods are desirable from the standpoint thatthey are unlikely to damage the die, the adhesives and carrier filmsrequired for such devices and processes are very expensive. UV-releasecarrier tapes have also been employed to a limited extent with galliumarsenide dice.

[0010] U.S. Pat. Nos. 4,990,051 and 4,850,780, each of which issued inthe names of Safabakhah et al., each describe an apparatus for removinga die from an adhesive carrier film. That apparatus concurrently appliesa vacuum to the exposed surface of the die and a chuck to the film onthe opposite surface of the die. The vacuum collett is moved away fromthe chuck, which facilitates a pre-peel of a small area of the film fromthe periphery of the die. A piston disposed coaxially within the chuckis then forced against the carrier film to stretch the film and furtherreduce the area of the film which adheres to the die, therebyfacilitating removal of the die from the film.

[0011] Some other apparatus for removing dice from a carrier filminclude a plunge-up piston which has a cap thereon to raise a select diein relation to the adjacent dice on the film. This process is referredto as “tenting” the film. A needle disposed within the cap is actuatedto contact the die from below and push it from the carrier film as avacuum tip positioned above the die pulls the select die away from thefilm.

[0012] Such tenting processes for removing dice from film areundesirable for several reasons. First, tenting sometimes creates an airbubble under the die, which tends to tilt the die, preventing the vacuumtip from obtaining a good hold on the die. In such cases, the vacuum tipwill likely drop the select die, damaging and/or contaminating the die.Second, in many such apparatus, the needles which push the select diefrom the film have pointed ends, which tend to score the bottom surfaceof the die. Dice which have been scored in such a manner tend tosubsequently fail mechanically at the location where they have beenscored. Third, as the film is tented, the edges of other dice which areadjacent to the select die may be chipped, causing damage to thecircuitry on their active surfaces, with consequential failure.

[0013] U.S. Pat. No. 4,915,565, issued in the names of Bond et al.,discloses an apparatus for removing a selected die from a wafer havingan array of dice which is attached to a carrier film. In the apparatusof the '565 patent, the dice are positioned beneath the film duringremoval of each selected die. A head having an array of needlesprotruding therefrom is positioned over the film opposite a selecteddie. In operation, the head plunges toward the film, the needlespenetrating the carrier film and dislodging the die from the film. Thedislodged die then falls into a receptacle. U.S. Pat. No. 4,759,675,issued in the names of Bond et al., discloses the same die removaldevice.

[0014] The sole use of needles to remove a select die from a carrierfilm makes the removal device of the '565 and '675 patents undesirable.The adhesive forces of the film to the die necessitate a large amount offorce for removing the die therefrom. Further, the orientation of theplunge head relative to the die requires that the die suffer some impactwhen falling into a receptacle, increasing the likelihood of damage tothe die.

[0015] U.S. Pat. No. 4,285,433, issued in the names of Garrett, Sr. etal., describes another method and apparatus for selecting and removingsingulated dice from a wafer. The apparatus includes an adhesive filmwhich is attached to the bottom of the carrier film supporting the dice.The adhesive film with adhered carrier film is pulled away from the dicethrough a slot. U.S. Pat. No. 4,607,744, issued in the name of Pak,discloses a similar method and device which removes carrier film fromdice with a take-up drum which pulls a free end of the carrier film. Thecarrier film is pulled around a separator edge into a slot, the dicethen passing over the separator edge and onto a conveyer whichtransports the dice away from the separator edge.

[0016] The amount of force applied to the dice as the carrier film ispulled downward through such a slot or separator edge while the diceproceed in a different direction of travel may be sufficient to break ordamage the dice. Further, the processes of the '433 and '744 patents areundesirable in that they do not permit automated removal of selecteddice from an array of dice including failed dice and die fragments, aswell as functional dice.

[0017] As dice become thinner and are fabricated with larger surfaceareas (which adhere to a greater area of the carrier film), thelikelihood of their being damaged by each of the foregoing mechanicalremoval processes increases.

[0018] Thus, an apparatus is needed for removing disposable carrier tapeor film from semiconductor dice and other electronic devices whichexerts little or no impact on a die, reduces the area of carrier tape orfilm adhered to a die before removal of the die, and utilizes aninexpensive yet effective carrier tape or film.

BRIEF SUMMARY OF THE INVENTION

[0019] In contrast to the deficiencies exhibited by the prior art, thelow-stress die removal system of the present invention addresses each ofthe foregoing needs. The apparatus is useful with many disposablecarrier tapes or films known and used in the art. The apparatus alsoexerts little, if any, impact on the die. The apparatus of the presentinvention also significantly reduces the surface area of carrier filmadhered to a die before removal. The die removal apparatus does notrequire the use of expensive films which have degradable adhesivesthereon.

[0020] One embodiment of the die removal apparatus of the presentinvention includes a base, including a plate member encircled by araised periphery, a screen disposed over the plate member, and a vacuumsource to create a vacuum within the base and below the screen. Theplate member may include recesses therein to ensure application of thevacuum to all portions of the base within the periphery. A carrier filmhaving dice on the upper surface thereof is placed above the plate, andthe vacuum used to pull the film against the screen and away from thedice.

[0021] In a variation of the die removal apparatus of the presentinvention, the plate member includes a series of laterally spacedsupports protruding upwardly therefrom. The portions of the screen whichoverlay the supports may be higher than those portions which rest withinthe recesses. Another variation of the base of the die removal apparatusof the present invention lacks a screen and merely employs supports.Alternatively, a plate member may be formed with apertures therethroughand the film is pulled thereagainst and with the aperture uponactivation of the vacuum source. In yet another variation, the upperface of the plate is provided with bumps, convolutions, or otherprotuberances separated by valleys into which the carrier film may bepulled.

[0022] In use, a frame ring which engages a carrier film with a waferthereon is positioned over the base. The film preferably rests upon andis supported by the plate member. As the vacuum source is activated, theportions of the carrier film which overlay the recesses are pulledagainst the screen, supports, or protuberances and into the recesses orvalleys. Thus, the area of the film which remains adhered to the dice isreduced by an amount which depends upon the size of the recesses and thestrength of the vacuum. Consequently, the adherence of each of the diceto the carrier film is reduced. Dice which have been selected forfurther processing (referred to individually as a “select die”) are thencompletely separated from the carrier film by a removal mechanism, whichremoves each select die by pushing, pulling, or pushing and pulling eachselect die from the film. Preferably, separation occurs while the filmis being pulled downward against the plate member.

[0023] The die removal apparatus according to the present invention mayalso include a vacuum head which is positionable above a select die. Thevacuum head pulls the die from the carrier film upon activation of avacuum source to pull a substantial portion of the film away from theback side of the die. When combined with the significantly reducedadhesion area of the film to the die, very little force is required toremove the die from the carrier film. Further, because the die restssecurely upon and remains supported by the plate member, tilting of thedie is unlikely.

[0024] The die removal apparatus may also comprise a low-impactplunge-up head which is positionable beneath a selected die and has oneor more needles which may be extended upwardly therefrom in atelescoping manner. After the plunge-up head is positioned beneath theselect die, the needle is actuated to push the die away from the carrierfilm. When combined with the significantly reduced adhesion area of thefilm to the die, afforded by the previously-mentioned base constructionand application of vacuum to the back side of the film, very littleforce is required to remove the die from the carrier film. Preferably,the plunge-up head is used in combination with a vacuum head which ispositionable above the select die. Preferably, when used in combination,as the plunge-up head needle pushes the die upward, the vacuum headsimultaneously lifts the die to transfer it to another location. As withthe first embodiment of the removal mechanism, the likelihood ofdamaging a select die is much less than that of methods which werepreviously known in the art.

[0025] Other advantages of the present invention will become apparent tothose of ordinary skill in the art through a consideration of theappended drawings and the ensuing description.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0026]FIG. 1a is a perspective view of a preferred embodiment of thepresent invention;

[0027]FIG. 1b is a cross-section of the base of the present invention,taken along line 1 b-1 b of FIG. 1a and showing an assembly including aframe ring, carrier film and a sawed wafer on the carrier film;

[0028]FIG. 2a is a cross-sectional view of a second variation of a baseof an apparatus according to the present invention;

[0029]FIG. 2b is a cross-sectional view of a third variation of a baseof an apparatus according to the present invention;

[0030]FIG. 2c is a cross-sectional view of a fourth variation of a baseof an apparatus according to the present invention;

[0031]FIG. 2d is a cross-sectional view of a fifth variation of a baseof an apparatus according to the present invention;

[0032]FIG. 2e is a cross-sectional view of a sixth variation of a baseof an apparatus according to the present invention;

[0033]FIG. 3 is a frontal perspective view of another variation of abase of an apparatus according to the present invention;

[0034]FIG. 4 is a cross-sectional view of an apparatus according to thepresent invention, also showing a first preferred embodiment of a dieremoval mechanism;

[0035]FIG. 5 is a cross-sectional view of an apparatus according to thepresent invention, illustrating a second preferred embodiment of a dieremoval mechanism;

[0036]FIG. 5a is a top plan view of a variation of a support plate ofthe present invention;

[0037]FIG. 6 is a cross-sectional view of a die removal mechanismaccording to the present invention;

[0038]FIG. 7 is a cross-sectional view of a second die removal mechanismof this invention;

[0039]FIG. 8 is a frontal perspective view of a variation of the base ofthe present invention, wherein the base is positionable relative to aselect die; and

[0040]FIG. 8a is a frontal perspective view of another variation of thebase, wherein the base is positionable relative to a select die.

DETAILED DESCRIPTION OF THE INVENTION

[0041] With reference to FIGS. 1a and 1 b, a first preferred embodiment100 of the low-stress die removal apparatus of the present invention isshown. Apparatus 100 includes a base 110, including a plate member 120,a screen 112 positioned over the plate member, and a vacuum source 114connected to the base beneath the plate member. Preferably, embodiment100 also includes a vacuum pick-up head 116, positioned above base 110.Vacuum pick-up head 116 is also operably connected to a vacuum source117, which may comprise vacuum source 114 or a second vacuum source.

[0042]FIGS. 1a and 1 b also depict a diced wafer 101 disposed upon acarrier film 104, which may also be referred to as a carrier tape, film,or tape. Diced wafer 101 includes several singulated dice 102 a, 102 b,102 c, etc. A frame 106, also referred to as a ring or a frame ring,supports carrier film 104 under tension for transport of wafer 101.Preferably, frame 106 has a shape and dimensions which facilitateplacement upon and connection with the top of base 110. Preferably, inembodiments of the invention where a plunge-up head 550 (FIGS. 6 and 7)is employed, the perimeter ring 111 of base 110 is of similar size toframe ring 106, there being enough lateral clearance between theperimeter ring and the periphery of wafer 101 for the plunge-up head tooperate. The foregoing elements are collectively referred to as waferassembly 108.

[0043] Base 110 includes a plate member 120 having an uneven, or bumpysurface, which includes a plurality of raised members 124 a, 124 b, 124c, etc. extending upwardly from the surface of the plate member, whichmay also be referred to as supports. Spaces 122 a, 122 b, 122 c, etc.are formed between supports 124 a, 124 b, 124 c, etc. Although FIG. 1ashows supports 124 in a staggered arrangement, the supports may also beconfigured in straight rows or in any other configuration whichfacilitates removal of carrier film 104 from a die 102 while adequatelysupporting the die. Similarly, while the top of each of the supports 124shown in FIG. 1a has a small surface area, other configurations ofsupports are also within the scope of the apparatus of the presentinvention, including, without limitation, horizontally elongatesupports, larger supports having a shaped (e.g., circular, square,rectangular, triangular, oval, n-sided polygonal and others) orthogonalcross-section with a hollow center, concentrically arranged shapedsupports, and other configurations of supports. The shape, thearrangement and the spacing of supports 124 are preferably sufficient tofacilitate pulling a significant portion of carrier film 104 from eachof dice 102. Yet, the shape, arrangement and spacing of supports mustalso adequately support each of the dice 102 and reduce the likelihoodof fracturing or otherwise damaging the die as portions of the film areremoved therefrom by a vacuum.

[0044] Referring to FIG. 1b, screen 112, which is preferably flexible,rests above plate member 120. Supports 124 a, 124 b, 124 c, etc. andspaces 122 a, 122 b, 122 c, etc. impart screen 112 with an unevensurface, which includes peaks 128 and valleys 130. Suitable materialsfor manufacturing screen 112 include, but are not limited to, wire mesh,silk screens, thin layers with a plurality of fenestrations formedtherethrough, and other meshes and screens which permit the flow of airtherethrough. Woven as well as punched screen materials may be employed.Anti-static materials are preferred.

[0045] Vacuum source 114 is operatively connected to base 110 throughvacuum port 115. As vacuum source 114 is activated, air is pulledthrough screen 112 and the carrier film 104 is pulled away from the dice102 until it contacts the screen material. Thus, vacuum source 114facilitates the removal of the portions of carrier film 104 whichoverlie valleys 130 from the backs of dice 102.

[0046]FIG. 2a illustrates an alternate variation of base 210, whereinthe screen 212 is a substantially flat member positioned above platemember 220. Plate member 220 includes supports, also referred to asraised members 224, extending upward therefrom through the screen, andforming a bumpy, or uneven surface above the plate member. Supports maybe arranged in straight rows, staggered, or in any other configurationwhich facilitates removal of the carrier film from the dice whileadequately supporting the dice.

[0047]FIG. 2b depicts a third variation 310 of the base, which includesa plate member 320 with a plurality of vacuum orifices 332 a, 332 b, 332c, etc. formed therethrough. Each of vacuum orifices 332 is operablyconnected to a vacuum source 314. Preferably, vacuum orifices 332 areconsistently spaced over substantially the entire surface of platemember 320. Embodiment 310 also includes supports, or raised members324, extending upwardly from the surface of plate member 320 to createan uneven surface thereon.

[0048]FIG. 2c depicts a fourth variation 340 of the base, wherein platemember 342 has a substantially flat bottom surface and an uneven topsurface having a plurality of peaks 344 and valleys 346 formed thereon.Plate member 342 may also include vacuum orifices 348 formedtherethrough which, upon activation of a vacuum source (not shown),facilitate the removal of gas from valleys 346. Alternatively, thevacuum source may connect to outside of the base through the sidewallthereof and adjacent the bottom, as long as the peaks 344 are higherthan the distance a carrier film may be drawn thereinto.

[0049]FIG. 2d illustrates a fifth variation 350 of the base, whichincludes a self-supporting, highly convoluted screen 352, which includesa plurality of peaks 354 and valleys 356. Screen 352 may be manufacturedfrom the same materials as those described above in reference to screen112 of FIG. 1b. As used herein, the term “screen” not only encompassesscreens having transversely dispersed woven elements, but may comprise aplurality of convoluted elongated elements extending in mutuallyparallel relationships, preferably with offset peaks and valleys inadjacent elements. Also, in an embodiment employing a screen withoutassociated discrete supports, it will be understood that the laterallyspaced peaks or protrusions of the screen comprise laterally spacedsupports.

[0050]FIG. 2e shows a sixth variation 360 of the base, which includes aplate member 362 with a plurality of upwardly extending support pins 364thereon. Each of the support pins 364 includes an enlarged head 366 atthe top thereof, against which a carrier film may be drawn.

[0051] Referring now to FIG. 3, another variation 370 of the base isshown. Base 370 includes a plate member 372 which has a plurality ofapertures 376 formed therethrough. A wafer assembly (not shown) issupported on supports 374, which are located between adjacent apertures376 of plate member 372. Preferably, supports 374 are narrow members.Apertures 376, which impart plate member 372 with a honeycomb-likeappearance, may have any shape, including, without limitation, circular,hexagonal, square, oval, and other shapes. Further, the walls definingthe aperture may be undercut, as shown in broken lines, to permit thefilm to be drawn lower in select areas.

[0052] Referring again to FIG. 1b, as an example of the use of the base110 of the apparatus of the present invention, the carrier film or film104, upon which a sawed, processed wafer 101 is positioned, is placedupon the base over screen 112. Frame ring 106 secures wafer assembly 108to base 110. Next, vacuum source 114 is activated, pulling air throughthe spaces 122, which pulls portions of carrier film 104 against thesurfaces of screen 112 which overlay the recesses, releasing thoseportions of the film from dice 102. Selected dice are then ready forremoval from carrier film 104. As defined herein, the terms “select die”and “selected die” refer to a die which has been selected for removalfrom sawed wafer 101 for further processing. In systems whereembodiments 210, 310, or other embodiments of the base of the presentinvention are employed, the methods for removing portions of the carrierfilm from the dice are substantially the same.

[0053] Referring now to FIG. 4, an embodiment 400 of a die removalmechanism is shown. Embodiment 400 includes a vacuum head 410, which ispositionable over a base 420 and operatively connected to a vacuumsource 430. Several dice 102 a, 102 b, 102 c, etc., which are disposedupon a carrier film 104, are shown. Vacuum head 410 is positionabledirectly above a select die 102 a. Systems which select dice, trackselect dice, and position a vacuum head above a select die, are eachwell known in the industry and are useful in connection with theapparatus of the present invention. Upon activation of vacuum source430, vacuum head 410 utilizes a vacuum to pull select die 102 a upwardfrom carrier film 104. Vacuum die pick-up mechanisms, which are wellknown and currently used in the industry, are useful in the system ofthe present invention.

[0054]FIG. 5 shows another embodiment of a die removal mechanism 500,according to the present invention, which includes a vacuum head 510 anda die plunge-up head, also referred to as striking mechanism 550. FIG. 5also shows several dice 102 a, 102 b, 102 c, etc. disposed upon acarrier film 104. The carrier film 104 is secured by a frame ring (notshown). Preferably, vacuum head 510 operates in substantially the samemanner as that described above in reference to FIG. 4.

[0055] Die plunge-up head 550 is of the type known and commonly used inthe industry. Die plunge-up head 550, which is positionable beneath aselect die 102 a, includes one or more needles 554 slidingly disposedwithin a holder 552. Plunge-up head 550 also includes an actuator 556disposed behind needle 554. Preferably, the size of plunge-up head 550is sufficient to include a plurality of needles 554, reducing thetendency of a die 102 to tilt as the needles strike the die. Systems forselecting good dice, tracking select dice, and positioning plunge-uphead 550 beneath a select die 102 a are well known in the industry andmay be used in connection with the apparatus of the present invention.Alternatively, the plunge-up head 550 may include another plunge-upmechanism such as a piston or a pressurized air line.

[0056] Actuators which are useful with die plunge-up head 550 include,without limitation, conventional two-way pneumatic actuators andsolenoid actuators, such as those which are known and used in theindustry, or any other type of actuator adaptable for use with plunge-uphead 550. Actuator 556 forces needle 554 upward with the appropriateamount of force and for the appropriate time period to, either directlyor indirectly, further loosen select die 102 a from carrier film 104without damaging the select die, then retract the needle into holder552. Preferably, in embodiments of the present invention, needle 554extends through a base aperture 553 to directly contact select die 102a.

[0057]FIG. 5 illustrates small base apertures 553. However, as FIG. 5ashows, the plate member 120′ may have a grid configuration. Supportmembers 124′ extend upwardly from intersecting portions of plate member120′, while large apertures 553′ are formed through plate member 120′ inthe spaces between the support members 124′.

[0058] Preferably, the needle has a raised tip with a convex tipsurface, or an otherwise blunt tip 555, which decreases the tendency ofthe needle to score the underside of the select die during actuation ofthe needle and contact of the needle with the select die, collectivelyreferred to as “striking” the die. In embodiments of the presentinvention where striking occurs while the frame, film and sawed waferassembly (reference character 108 in FIG. 1a) is positioned over thebase, blunt tip 555 also prevents perforation of carrier film 104 duringstriking. Perforation of carrier film 104 could cause a loss of thevacuum that pulls the film away from the dice 102. In such embodiments,needles 554 pass through the plate member and/or the screen duringstriking.

[0059] Turning again to FIG. 1a, the preferred dimensions of frame ring106 are such that the distance between the outer periphery of wafer 101and the inner surface of the frame permits the plunge-up head 550 (seeFIGS. 6 and 7) to further remove carrier film 104 from the outermostcomplete dice without contacting the frame.

[0060] Preferably, in operation, the plunge-up head does not disrupt thevacuum which pulls portions of the carrier film from the dice. Thus, asFIG. 6 illustrates, a preferred embodiment of base 610 includes an arrayof base needles 670 a, 670 b, 670 c, etc. therein, each of which areslidingly engaged within needle ports 676 a, 676 b, 676 c, etc.,respectively. Needle ports 676 are each formed through plate member 620.Each base needle 670 includes an actuation end 672 and a needle tip 674.The actuation end 672 of each base needle 670 is preferably exposed tothe lower, outer surface of plate member 620. Preferably, tip 674 ofeach base needle is raised, with a convex surface, or otherwise blunt toprevent scoring of a select die 102 a as the needle tip comes intocontact with the select die. Blunt needle tip 674 also preventsperforation of carrier film 104 as needle 670 is actuated, whichfacilitates maintenance of the vacuum which pulls portions of the filmaway from dice 102. Preferably, each base needle 670-needle port 676assembly is sealed in order to maintain the vacuum which has beencreated in base 610. Alternatively, a positive pressure collett could beemployed in place of a plunge-up head by directing pressurized airupward against needle 670 to drive the needle against select die 102 a.

[0061] As an example of the operation of plunge-up head 550 in thepresent embodiment of base 610, the plunge-up head is positioned beneaththe base needle 670 or base needles located beneath select die 102 a. Asthe plunge-up head needle 554 is actuated, it moves upward, contactsactuation end 672 of base needle 670, and forces the base needle upwardagainst the select die to further loosen the select die from carrierfilm 104.

[0062] With reference to FIG. 7, another preferred embodiment of thebase 710 includes a sealed plunge-up head housing 780, within whichplunge-up head 550 is disposed. In addition to creating a vacuum withinbase, vacuum source 714 creates a vacuum within plunge-up head housing780. Plunge-up head 550 is repositionable within housing 780 withoutdisrupting the vacuum therein. Thus, base 710 permits direct contact ofneedle 554 through plate member 720 and the screen thereon, if any, withselect die 102 a to further remove the select die from carrier film 104.

[0063] With reference to FIG. 8, another embodiment of the apparatus ofthe present invention includes a small base 810, including an unevenfilm removal surface as described above in reference to FIGS. 1b, 2 athrough 2 e and 3. Base 810 is positionable beneath a select die 102 aon a wafer assembly 108 using known apparatus and methods. Base 810 isattachable to a vacuum source (not shown) at connector 812. A diepick-up mechanism 820, as described above in reference to FIG. 4, mayalso be used in connection with positionable base 810.

[0064] In use, positionable base 810 is oriented beneath select die 102a and,positioned in close proximity to the carrier film attached to theselect die. The vacuum source is actuated, pulling air from the lowerareas of the base and removing portions of the carrier film from selectdie 102 a, thereby reducing the adhesion of the film to the die. Ifdesired, the vacuum may be applied continuously, the base then slidinglaterally to different locations beneath the carrier film. Die pick-upmechanism 820 then completely removes select die 102 a from the carrierfilm.

[0065]FIG. 8a shows an alternative embodiment 810′ of a positionablebase. Base 810′ is adapted to fit over a die plunge-up mechanism 830,having a needle 840, piston, pressurized air line, or other plunge-upmechanism therein.

[0066] Referring again to FIG. 5, as an example of the use of embodiment500 of die removal mechanism, vacuum head 510 is positioned above aselect die 102 a and plunge-up head 550 is positioned beneath the selectdie. Vacuum head 510 is lowered toward select die 102 a. Plunge-up head550 is raised to an appropriate position beneath select die 102 a.Vacuum source 530 is activated to direct a vacuum through vacuum head510 and at the exposed surface of select die 102 a. Preferably, whilevacuum head 510 is pulling die 102 a, needle 554 is actuated by actuator556 to strike the select die and further remove carrier film 104 fromthe select die. In embodiments of the present method wherein removal ofselect die 102 a occurs while assembly 108 is disposed upon the base,each needle 554 passes through the plate member and the screen, if any,during striking. Vacuum head 510 is then raised while holding die 102 a,and transfers the select die to a desired location. When embodiment 610of the base, discussed above in reference to FIG. 6, is used in thepresent method, needle 554 contacts actuation end 672 of the appropriatebase needle 670, which contacts carrier film 104 beneath select die 102a to further remove the film from the die.

[0067] Inexpensive carrier films may be used with the present inventionin lieu of those coated with UV-degradeable or other expensiveadhesives, or adhesives which contaminate the dice. For example, thepressure sensitive adhesive-coated polymer films manufactured byShinkawa and Nitto, both of Japan, which are used for protectivelycoating sheet steel, are particularly useful in the invented system.Such films are desirable for use because of their low cost and chemicalcleanliness (i.e., will not contaminate dice), both of which advantagesprovide a reduction in manufacturing costs.

[0068] Another consequent advantage of the invention is that thelikelihood of dropping, contaminating, fracturing or otherwise damagingthe die is much reduced when compared with methods which were previouslyknown in the art.

[0069] While the invention has been described in terms of a vacuumdrawing the carrier film down and away from the dice supported thereon,those of ordinary skill in the art will recognize that it is a pressuredifferential which effects movement of the film. Accordingly, it is alsocontemplated that a higher (positive) pressure may be applied to the topof the carrier film to “push” the film downward against ambient pressuretherebelow. Specifically, a push-up head may be employed within abell-type chamber placed over the frame ring and carrier film to effectwithdrawal of large portions of the film from the dice.

[0070] Although the foregoing description contains many specificities,these should not be construed as limiting the scope of the presentinvention, but as merely providing illustrations of some of thepresently preferred embodiments. Similarly, other embodiments of theinvention may be devised which do not depart from the spirit or scope ofthe present invention. The scope of this invention is, therefore,indicated and limited only by the appended claims and their legalequivalents, rather than by the foregoing description. Additions,deletions and modifications to the embodiments of the invention asdisclosed, and the combination of features of different embodiments, arespecifically contemplated as falling within the scope of the invention.

What is claimed is:
 1. A method for reducing adherence of an adhesivecarrier film to a semiconductor die, comprising: placing the adhesivecarrier film proximate to a plurality of laterally spaced supportmembers with the semiconductor die on an opposite side of the carrierfilm from said support members; and drawing the adhesive carrier filmbetween said support members to reduce adherence of the adhesive carrierfilm to the semiconductor die.
 2. The method of claim 1, furthercomprising pulling a substantial area of the adhesive carrier film awayfrom the semiconductor die.
 3. The method of claim 1, further comprisingremoving the semiconductor die from the adhesive carrier film.
 4. Themethod of claim 3, wherein said removing is effected by applying avacuum to a surface of the semiconductor die not in contact with theadhesive carrier film.
 5. The method of claim 1, further comprisingstriking a back surface of the semiconductor die through the adhesivecarrier film.
 6. The method of claim 3, further comprising striking aback surface of the semiconductor die through the adhesive carrier film.7. The method of claim 1, wherein said drawing is effected by applying anegative pressure to the adhesive carrier film.
 8. A method for reducingadherence of an adhesive carrier film to at least one semiconductor die,comprising: disposing the adhesive carrier film, adhered to a back sideof the at least one semiconductor die, adjacent to a support including aplurality of laterally spaced support members; and drawing portions ofthe adhesive carrier film located between said plurality of laterallyspaced support members away from the back side of the at least onesemiconductor die.
 9. The method of claim 8, wherein said drawingcomprises applying a vacuum to said portions of the adhesive carrierfilm located between said plurality of laterally spaced support members.10. The method of claim 8, further comprising pulling a substantial areaof the adhesive carrier film away from the at least one semiconductordie.
 11. The method of claim 8, further comprising removing the at leastone semiconductor die from the adhesive carrier film.
 12. The method ofclaim 11, wherein said removing is effected by applying a vacuum to asurface of the at least one semiconductor die not in contact with theadhesive carrier film.
 13. The method of claim 8, further comprisingapplying pressure to a back surface of the at least one semiconductordie through the adhesive carrier film.
 14. The method of claim 13,wherein said applying pressure comprises striking said back surface.